Polycomb Repressive Complex 1 Is Required to Maintain Stem Cell Identity and to Preserve Adult Tissue Homeostasis.

The study highlighted the critical role of Polycomb Repressive Complex 1 (PRC1) in maintaining stem cell identity and tissue homeostasis, particularly in LGR5 expressing stem cells. PRC1 was essential for repressing non-lineage specific transcription factors, thereby preserving stem cell identity and supporting the WNT pathway crucial for self-renewal. Loss of PRC1 function in intestinal stem cells led to severe tissue maintenance defects, while in hair follicle stem cells, it activated an epidermal program, indicating tissue-specific transcriptional outcomes. The research also explored the complexity of PRC1, composed of various subunits forming different sub-complexes, and their roles in adult tissue maintenance, using conditional knockout mouse models to investigate the specific contributions of these complexes.